1. Field of the Invention
The present invention pertains to the field of evacuating and sealing containers, including methods and apparatus for removing fluid from a container and sealing the container.
2. Background
Consumers frequently use vacuum storage containers to preserve items in an environment from which all or most of the fluid in the container, typically air, has been removed. Storing food in a vacuum-sealed bag, for example, may help preserve flavor, may make food last longer, and may prevent freezer burn.
Items other than food can also be kept in vacuum storage bags or containers. Articles of clothing, flower seeds, matches, etc., stored in evacuated containers can be kept secure from external elements. Photos or other documents may also be protected and preserved.
Vacuum bags are also beneficial for compressible items. When air is removed from a bag in which a compressible item is placed, the stored item may be significantly compressed so that it is easier to transport and requires substantially less storage space.
Uses of the vacuum storage bags can be divided into two main categories: 1) single use vacuum storage bags and 2) multiple use vacuum storage bags. Single-use bags are typically used in industrial operations and in home kitchen use. For the industrial application, products are typically sealed in a vacuum pouch or bag for transport and storage. These vacuum pouches or bags are usually thrown away by the consumer after one use. While some industrial vacuum pouches now come with a resealable feature, the bags are meant to be thrown away when the consumer is finished with the contents and the pouches or bags are not vacuum-sealed again. For the home kitchen application, leftovers and other foodstuffs that have been opened are placed in a vacuum bag, sealed and the bag evacuated. When, for example, the leftover is going to be eaten, the vacuum bag is usually cut open to allow access to the contents. If the leftover is again not completely eaten, if it is to be saved, it will typically be placed in a new bag, which is sealed and evacuated.
Multiple-use vacuum storage bags are becoming more popular and are currently mainly used by consumers for storing items such as food or compressible household products (i.e., towels, pillows, etc) to save space.
Currently, most single use vacuum storage bags such as the Deni FRESHLOCK (U.S. Pat. No. 5,048,269 to Deni, et. al) evacuate air from the bag; through the same opening through which the item is placed into the bag. Once the desired vacuum is created inside the bag, the bag is permanently sealed in that the bag must be cut open to access the item inside the bag. To accomplish the sealing, typical vacuum machines require extra material around the opening in which the item is inserted to allow for proper sealing. If the user wants to reuse the bag, air is evacuated through the newly cut opening and, if possible, permanently sealed again. However, the bag becomes smaller each time it is cut open, evacuated, and resealed. Eventually, the bag becomes too small and must be discarded. The result is a considerable waste of material and money. To have a truly reusable bag, it is desirable to be able to temporarily seal the opening through which the item is inserted and evacuate the bag from a different opening such as a valve on the side.
One type of known valve system is disclosed in U.S. Pat. No. 6,634,384 to Skeens et al. In the Skeens et al. system, a hole is placed in one side of the bag and a sturdy, one-way reusable valve is inserted and attached to the side of the bag. However, it is a plastic piece added to the bag not an integral piece of the bag itself, which requires additional manufacture, added bulk to the bag and expense. A disadvantage of this valve is that if the stem is accidentally depressed the seal to the bag will be broken causing undesirable spillage or the need to re-evacuate the bag.
Another drawback to the use of current vacuum storage bag systems is the cumbersome vacuum packaging apparatus used to evacuate air from the bags. Typical vacuum packaging apparatuses are designed such that they require a significant amount of table or counter space and are as wide as the bag opening. One such vacuum apparatus developed by Yen Lau, et al. (U.S. Pat. No. 5,287,680) addressed the size of the vacuum apparatus. The Yen Lau patent described a small hand held vacuum device that would close a bag having a resealable top except for a small part of the opening through which a vacuum nozzle was inserted. When the bag was sufficiently evacuated the nozzle would be removed. Unfortunately, air reenters the bag when the device is removed and the desired vacuum is lost as the remaining length of the bag is sealed by hand.
In addition, typical vacuum storage bag systems include heat sealers that may be limited in their ability to seal effectively or lack the ability to seal a wide variety of different bag styles, shapes and sizes. The devices designed to address this issue, for example, devices that use run through heat sealers that can accommodate different size bags are difficult to use reliably. If the user runs the sealer over the opening of the bag too quickly, a consistent vacuum type seal will not be formed. However, if the user runs the sealer too slowly, then the bag will melt. Other heat sealers that use rollers can have a bunching problem. If one of the rollers runs quicker than the other the bag can bunch in the corner, creating an incomplete seal.
On the industrial application side, the single use vacuum bag systems are quite cumbersome. U.S. Pat. No. 2,649,234, issued to Taunton, describes an early system for creating airtight packages. That system takes a pre-sealed bag and creates a slit in one of the side sheets. To accomplish this once the bag is placed in the system, suction is applied to the exterior of the bottom sheet of the bag to pull the bottom sheet away from the opposing top sheet. This creates a space between the top and bottom sheet to allow a piercing tool to pierce only the bottom sheet, leaving the non-pierced top sheet to maintain a seal to allow air to be evacuated from the bag. The area around the slit is then heat-sealed. The Taunton system is a very complex system. For example, in the Taunton system, the piercing tool must be adjusted properly to ensure that both the top and the bottom sheets are not pierced. In Taunton if the piercing tool is misadjusted and pierces both sheets, it would not be possible to evacuate the bag since Taunton relies on the top sheet to form part of the necessary seal during evacuation. Also in the Taunton system the bag material must be sufficiently compliant and consistent to reliably be able to create the appropriate air pocket between the top and bottom sheets.
For these and the following reasons, there is a need for a more compact, reusable method and apparatus for evacuating and sealing containers that address the foregoing disadvantages and problems.